Equirectangular projection: Difference between revisions

Revision as of 09:24, 2 November 2020

Revision as of 17:17, 4 December 2020

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[[File:Plate Carrée with Tissot's Indicatrices of Distortion.svg|thumb|upright=1.75|Equirectangular projection with [[Tissot's indicatrix]] of deformation]]

[[File:Blue Marble 2002.png|thumb|upright=1.75|True-colour satellite image of Earth in equirectangular projection]]

The '''equirectangular projection''' (also called the '''equidistant cylindrical projection''', '''geographic projection''', or '''la carte parallélogrammatique projection''', and which includes the special case of the '''plate carrée projection''' or '''geographic projection''', historically also '''plane chart'''<ref>https://mathworld.wolfram.com/EquirectangularProjection.html</ref>) is a simple [[map projection]] attributed to [[Marinus of Tyre]], who [[Ptolemy]] claims invented the projection about AD 100.<ref>''Flattening the Earth: Two Thousand Years of Map Projections'', John P. Snyder, 1993, pp.&nbsp;5–8, {{ISBN|0-226-76747-7}}.</ref> The projection maps [[Meridian (geography)|meridians]] to vertical straight lines of constant spacing (for [[Meridian (geography)|meridional]] intervals of constant spacing), and [[circle of latitude|circles of latitude]] to horizontal straight lines of constant spacing (for constant intervals of [[Circle of latitude|parallels]]). The projection is neither equal area nor [[Conformal map projection|conformal]]. Because of the distortions introduced by this projection, it has little use in [[navigation]] or [[cadastral]] mapping and finds its main use in [[thematic map]]ping. In particular, the plate carrée has become a standard for global [[Geographic information system#Raster|raster datasets]], such as [[Celestia]] and [[NASA World Wind]], because of the particularly simple relationship between the position of an [[pixel|image pixel]] on the map and its corresponding geographic ___location on Earth.

==Definition==